Method of sealing bottles and the like



3- A. BURKARDT 2,326,722

METHOD 0r SEALING BOTTLES AND THE LIKE Filed April '7, 1942 HUI!!! m u HIIIIIII'HI v ORNEY other auxiliary holding devices.

thermoplastic coatings on both faces of the base material and whichzthermoplastic coatings have 25 I Fig. 1 is a side eleyationwf a portion of the of a milk bottle having in position thereon a closure'of the hood seal type embodyingjhe invention/and illustrating a manner in which the 'same is applied to the bottle;

improved .50

Patented Aug. 10, 1943 UNITED STATES. PATENT. OFFICE,"

Anton .Burkardt, New York, N. Y., assignor to Pneumatic Cap & Seal Corporation, New York, N. Y., a corporation of Delaware Application April 7, 1942, Serial No. 437,949

3 Claims. The present invention relates to bottle closures or covers, and more particularly to an improved material for making such covers. 3

The material forming a part of the subject matter of the present invention is an improved material of the nature of a thermoplastically coated material, the base being of any suitable fibrous material, such as paper preferably per-se untreated with thermoplastic material and coated with a thermoplastic material on both faces. 10

Preferably the thermoplastic coating on one face of the material has a diflerent zone of tackiness than the thermoplastic material onthe other face.

This material is particularly advantageous in' 15 the making of bottle closures, and particularly bottle closures of the hood seal type and whereinthe thermoplastic coatings upon the skirt portion of the hood seal are rendered tacky by heat and form a band which retains the hood seal in position on the bottle without the use of wires or By the use of different ranges of temperature zones of tackiness and by applying suitable heat sealing means to embrace under pressure the skirt portion of the hood seal, heat is transferred through the outer thermoplastic coating and through the paper to 3 the inner thermoplastic coating to render both coatings tacky, and upon withdrawal of such heat sealing means, the skirt portion of the hood seal is formed into a band, retaining the hood seal in cient degree of yieldabilityrto permit the hood 0 preforming operation without undue breakage of either the base material or of the thermoplastic coatings thereon.

In the accompanying drawing,

Fig. 2 is a plan view of a blank of my material from which the hood seal" shown-in Figure 1 may be made;

Fig. 3 is a detail sectional elevation, taken on the linei'33 of Fig. 2;

' Fig. 4 is a fragmentary section ofa punch'and 55 die for preforminga hood seal of the type shown in Fig. 1 from a blank such as is shown in Figures 2 and 3;

Fig. 5 is a side elevation of the upper portion of a milk bottle, having in position thereon, a pre-formed hood seal, indicated in Fig. 4; and

Fig.- 6 is aview, similar to Fig. 5, showing heat sealing means applied to the skirt portion of the hood seal at the stage of compacting and handing the skirt portion into a holdingring.

Referring to Figs. 2 and 3 of the drawing, 10 designates. generally a blank oisuitable sheet material stamped from a blank of indeterminate length and width. Such blank comprises a core I! of suitable fibrous material such as paper and of proper gauge, the body of such fibrous material being per se untreated, but bearing on its opposite faces the thermoplastic coatings I2 and I3 respectively. when subjected to-pressure and thereafter cooled,

. terial from which blanks may be made, the blanks Iii are formed of 'sulphite paper of approximately .007" thick, and of aMullen test of from 55 to 58. The outer coating I3 is made from Vinylyte or similar thermoplastic material, approximately .00025" thick, rendered tacky under heat of approximately 180 F. applied for about a one-half second. The inner coating I2 is made from Vinylyte or similar thermoplastic material, rendered tacky under heat of approximately 135 F. applied exteriorly for about a one-half second. As a commercial form of these substances available in the open market, the higher temsecure position about the mouth and the neck perature thermoplastic Vinylyte' is known as VYHF, and the low temperature thermoplastic,

Vinylyt'e is known as VYLF,

With the above materials, in the form described herein, when heat of approximately 350 F. is applied to the outer coating l3 for approximately one-half second, heat is transferred through the paper. 10 to, the inner coating l2,

' and such coating iris brought to its state of tackiness at approximately 135 F. at substantially the same instant as the coating l3.- The degree of heatv applied and. the length of time of application thereoi are controlling iac- .tors in determining the selection of thegproper thermoplastic materials to be used. :For example,-if-' the outer thermoplastic ma the application of heat becomes t proximately 259 F. for approximately one lfili second, then the inner thermoplastic material l2 should reach its state of tackin ess at approximately F.

In standard practice, the paper I is sulphite paper .0007 thick, with a Mullen test of 55 to 58, and for optimum results the thickness \of the coatings l3 and l2 are each .00025 thick, and

'the directions herein given have been calculated Fig. 4, whereupon a plunger l6 of proper length and diameter forces the blank l0 frombetween v the members l4 and I5 and downwardly through the opening in thedie l4.

Preferably, as shown, the resulting hood seal 11, shown in inverted position in Figure 4, and in proper position in Figure 5 on the top of a bottle l8, such as a milk bottle, has its skirtportion preformed with a series of substantially parallel linear indentations, for a purpose set forth more fully hereinafter.

1 Upon placing the preformed hood seal upon the bottle l8, suitable heating elements l9 and 20, advantageously electrically heated heating elements, brought to the proper temperature, as above set out, are moved inwardly under pressure toward each other, as indicated in Figure 6, the skirt portion of the hood seal I1 is subjected to pressure causing pleats to. form in the skirt portion defined by the preformed parallel linear indentations, and the heat imparted by the heating elements l8 and raises the temperature of the outer thermoplastic coating I3, causing I heat to be transmitted through the core H and thence to the inner thermoplastic coating l2. Upon withdrawal of the heating elements I9 and .20 from the skirt portion of the hood seal, the

thus formed pleats are bonded to one another uponiboth faces of the skirt portion ofthe hood seal, and form a band, conforming the skirt por- 1 tion to the formation of the neck of the bottle and maintaining the hood seal 11 in position on the top of the bottle, as clearly shown in Figure-l. Whereas'the invention hasbeen set forth by reference to specific forms thereof, it will be understood that many ,changes and modifications made be made without departing from the spirit of the invention, as defined by the appended claims.

I claim: I 1. That improved method of forming and applying a hood seal, which comprises applying to a bottle mouth a sheet of fibrous material per 5 se untreated, of a predetermined thickness and having a coating of thermoplastic material on each face thereofithe thermoplastic material on the inner face of the hood seal having a zone of tackiness at a lower temperature than the ther-' l0 moplastic material on the outer face thereof,

applying heat and pressure to the outer coating to thereby bring the outer thermoplastic material and the inner thermoplastic material substantially simultaneously to their respective zones of 5 tackiness and .to interfold the skirt portion of 20 .007" thick having on the outer face thereof a coating of thermoplastic material approximately .00025" thick and adapted to be rendered tacky under heat of approximately 350 F. applied for one-half second, and a coating on its inner face of thermoplastic material approximately .00025" thick and adapted to be rendered tacky under heat of approximately 135 F. applied for onehalf second, whereby upon application of heat of approximately 350 F. for a period of approxi mately one-half second; both the outside and the inside coating of thermoplastic materials are brought practically simultaneously to their respective zones of tackiness.

3. A hood seal for bottles comprised of a cuphaped core of fibrous material of approximately .007 thick having on the outer face thereof a coating of thermoplastic material approximately .00025" thick and adapted to be rendered tacky under heat Off approximately 350 F. applied for one-half second, and a coating on its inner face of thermoplastic material approximately .00025" thick and adapted to be rendered tacky under heat of approximate 135 F. applied for one-half second, the skirt portion of the hood seal being interfoldedto form a band.

ANTQN BURKARDT.

and 

